Model Output Discussions 18z 31/01/2016

[I remember Atlantic 252]

1 minute ago, mcweather said:

Yes Nick I would be calling this another ECM240 up the garden path job were it not for the fact that it is almost identical to the latest GFS 12Z AT 252.

Want that to come off then! 12 times in a row

[nick sussex]

I'm frustrated on one hand and relieved on the other! Both the GFS and ECM agree on a diving low se'wards. Both also agree on lifting those deeper low heights n away from Scandi, the effect is to give a signal for pressure to rise there.

The issue at the moment is how much cold will be on tap. I seriously don't want to see another on the face of it good synoptic set up ruined by the lack of cold.

Its at times like this that you want to bang your head against a wall because as we enter the end of winter we're chasing those more elusive deeper cold pools which of course with the same set up its easier to find earlier in the winter.

So the key going forward is to see deeper cold setting up to the east/ne.

It might be that these better synoptics may well continue to evolve with higher latitude blocking especially in light of the MJO.

[blizzard81]

8 minutes ago, nick sussex said:

I'm frustrated on one hand and relieved on the other! Both the GFS and ECM agree on a diving low se'wards. Both also agree on lifting those deeper low heights n away from Scandi, the effect is to give a signal for pressure to rise there.

The issue at the moment is how much cold will be on tap. I seriously don't want to see another on the face of it good synoptic set up ruined by the lack of cold.

Its at times like this that you want to bang your head against a wall because as we enter the end of winter we're chasing those more elusive deeper cold pools which of course with the same set up its easier to find earlier in the winter.

So the key going forward is to see deeper cold setting up to the east/ne.

It might be that these better synoptics may well continue to evolve with higher latitude blocking especially in light of the MJO.

It really would sum this winter up if we finished it off with a stonking easterly but uppers not cold enough for snow!

[nick sussex]

28 minutes ago, blizzard81 said:

It really would sum this winter up if we finished it off with a stonking easterly but uppers not cold enough for snow!

Yes that North Sea is both a help and hindrance in these types of set ups. You want the warmer sea to provide the convection but need sufficiently cold uppers to produce the snow.

In terms of the earlier disagreements upstream that appear within T96hrs NCEP have not included the GFS 12hrs run in their short tern outlook. They're happier with the ECM/UKMO.

 

Edited February 17, 2016 by nick sussex

[Man With Beard]

OK all aboard for another masochistic snow chase! Time place: Monday morning / England & Wales. Situation: highly marginal back edge snow event, likely to just fall short of a blizzard. See how the -5C line on the ECM op falls just short of the main band of rain:

Edited February 17, 2016 by Man With Beard

[LeeTofficial]

1 minute ago, Man With Beard said:

OK all aboard for another masochistic snow chase! Time place: Monday morning. Situation: highly marginal back edge snow event, likely to just fall short of a blizzard. See how the -5C line on the ECM op falls just short of the main band of rain:

Place your bets now

[Cheshire Freeze]

I can't believe that NWly and Nly airflows have become so marginal in recent times. Seems you get an initial push of conducive uppers before a gaping mild sector appears. Time and time again just recently.

[on the coast]

14 minutes ago, Man With Beard said:

OK all aboard for another masochistic snow chase! Time place: Monday morning / England & Wales. Situation: highly marginal back edge snow event, likely to just fall short of a blizzard. See how the -5C line on the ECM op falls just short of the main band of rain:

Nothing I can see from the latest model runs to suggest anything noteworthy for cold and widespread snowfall. Again it's all very marginal.

[Grimsby Snow Lover]

7 minutes ago, CreweCold said:

I can't believe that NWly and Nly airflows have become so marginal in recent times. Seems you get an initial push of conducive uppers before a gaping mild sector appears. Time and time again just recently.

Agreed! we are currently nearing the end of a cold spell and what amazes me is that the temperatures have been average at best. Since when has average temperatures been classed as a cold spell? when was the last time Shetland and Aberdeen got hammered by frequent heavy snow showers in a northerly flow?

Edited February 17, 2016 by Grimsby Snow Lover

[karyo]

8 minutes ago, CreweCold said:

I can't believe that NWly and Nly airflows have become so marginal in recent times. Seems you get an initial push of conducive uppers before a gaping mild sector appears. Time and time again just recently.

January was a record breaker in the Arctic so not a surprise. We live in sad times.

[feb1991blizzard]

7 minutes ago, CreweCold said:

I can't believe that NWly and Nly airflows have become so marginal in recent times. Seems you get an initial push of conducive uppers before a gaping mild sector appears. Time and time again just recently.

Its because they have all been toplers, you need the high much further North to get the frigid air down, 17th /18th dec 2010 only bought the goods to me once the wind swung around to a WNW flow, but it was such frigid air that was straight from the Arctic originally.

[blizzard81]

21 minutes ago, CreweCold said:

I can't believe that NWly and Nly airflows have become so marginal in recent times. Seems you get an initial push of conducive uppers before a gaping mild sector appears. Time and time again just recently.

I totally agree, I remember you mentioning this earlier in the season. North east US and Canada managed to get their brutal cold vacuum cleaner out again and sucked it all their way - AGAIN!

[bobbydog]

1 hour ago, sawan said:

and what are the caveats please???? I think we shouldn't be biased around what we desire. These charts are bound to change significantly by the time we reach t48.

well... the "caveats" are (as they usually are if you follow this thread) that it is 4 days away and things can dramatically change very quickly. the point is, it has been shown quite consistently over a few runs, so is a stronger than usual signal for snow. the charts themselves are only a rough guideline,  as they will not be showing the exact precip locations at this range. as far as "biased around what we desire" goes, i posted several charts to show that its not just a favoured cherry picked one, even though it is just one day of snow. personally i love snow but i'm under no illusions that it will be ( as the GFS was showing when i posted) anything other than a quick snowy snap. some people on here will be happy with that and thats fine- thats who its really aimed at. for me, i want a couple of feet of snow so i can blast about in my land rover to give it a real test- but thats not going to happen this year.

so its not what i personally want-but to be fair, i can post what the models are showing at any given time without having to give "caveats". i'm merely participating in the 'model output discussion'

[Faronstream]

This night a mini low pressure from Germany will travel up to S Sweden and finally give some  snow, too bad it's just about 2-5cm at most

And overall i think ECMWF have been colder last runs with more chance of accumulated snow for most of UK upcoming week

[Snowy L]

53 minutes ago, CreweCold said:

I can't believe that NWly and Nly airflows have become so marginal in recent times. Seems you get an initial push of conducive uppers before a gaping mild sector appears. Time and time again just recently.

Yep I remember Christmas 2004, Northwesterly just 2 days after plus 5 uppers were over the UK, brought snow accumulations to my area easily. North-westerlies are useless now unless you're inland and on higher ground.

Edited February 17, 2016 by Snowy L

[mountain shadow]

19 minutes ago, Snowy L said:

Yep I remember Christmas 2004, Northwesterly just 2 days after plus 5 uppers were over the UK, 

I think you mean minus 5 uppers.

[I remember Atlantic 252]

+5 uppers, poster is right, was a very good Xmas well timed toppler

[Lukesluckybunch]

Is it me,or is the ecm a very good run!

[Snowy L]

15 minutes ago, mountain shadow said:

I think you mean minus 5 uppers.

Messed up my grammar. I meant on the 23rd we had plus 5 uppers over England, yet 2 days later precipitation was falling as snow here in a northwesterly wind.

 

Is it me,or is the ecm a very good run!

 

Both ECM and GFS show good potential for blocking to our Northeast at day 9. Problem is there is a real lack of cold air over Scandi and Russia at the moment thanks to a huge HP bringing Southerly winds to those regions.

Edited February 17, 2016 by Snowy L

[Lukesluckybunch]

Blocking to northeast from Monday though,a block looks like forming in the Atlantic Northwest.not the northeast..?? Towards end of week we see  pressure rise to northeast

Edited February 17, 2016 by Lukesluckybunch

[Cheshire Freeze]

38 minutes ago, Snowy L said:

Yep I remember Christmas 2004, Northwesterly just 2 days after plus 5 uppers were over the UK, brought snow accumulations to my area easily. North-westerlies are useless now unless you're inland and on higher ground.

Yep, 2004 was just a bog standard toppler too. However, it pees all over anything we've seen from that direction over the past few years and anything that's currently showing within the NWP. Even March 2006 saw a decent plunge from that direction. Baffling.

[winterof79]

Here is the most up to date output for now and trust me it aint snowing and the fronts gone ages ago

We do not have a cat in hells chance of relying on these snow charts for Sunday.....I rest my case your honour

Edited February 17, 2016 by winterof79

[Pembroke Dangler]

2 minutes ago, CreweCold said:

Yep, 2004 was just a bog standard toppler too. However, it pees all over anything we've seen from that direction over the past few years and anything that's currently showing within the NWP. Even March 2006 saw a decent plunge from that direction. Baffling.

I too have been baffled, but looking at the northern hemisphere as whole during the last 3 winters it seems to me that due to the elongated PV heading into North America and the east of Asia it's more rugby ball shaped so it just leaves dregs of cold to tap into on our side of the globe which means the Atlantic gets mixed in easier from a north or nw wind direction. 

[lukemc]

13 minutes ago, CreweCold said:

Yep, 2004 was just a bog standard toppler too. However, it pees all over anything we've seen from that direction over the past few years and anything that's currently showing within the NWP. Even March 2006 saw a decent plunge from that direction. Baffling.

Crewe Cold,

Well wouldn't you count Boxing Day 2014 in that category too? which I would class as a toppler scenario and that brought snow on the ground here in Liverpool upper temps were not amazing btw so it can happen - we also had transitional lying snow in Liverpool from a NW'ly last year in January I can recall so as least as far as my area is concerned that is not correct they can still deliver if the parameters are right.  It can also depend on the intensity and amount of precipitation you get to bring evaporative cooling increasing the risk of snow at low levels.

EDIT - also remember we got snow from a transitional NW'ly again in December 2011.

It might have been different in Crewe but that was for my location in Liverpool not far from the Irish Sea coast even though snow is infrequent at our location it goes to show it is not impossible of course - and the examples above are of toppler type events not even including the likes of 2010.

 

 

Luke

Edited February 17, 2016 by lukemc

[Eskimo]

13 minutes ago, winterof79 said:

Here is the most up to date output for now and trust me it aint snowing and the fronts gone ages ago

We do not have a cat in hells chance of relying on these snow charts for Sunday.....I rest my case your honour

If it's any consolation, that chart is for 1am tomorrow morning and is the super-low res version of the GFS 0.5 high-res charts.